Chapter 13 - Sequences and Series - 13.1 Sequences - Exercises and Problems for Section 13.1 - Exercises and Problems - Page 539: 1

Not an arithmetic sequence.

In order for a sequence to be arithmetic, the difference of all consecutive terms must be constant. Here: $a_2-a_1=7-2=5$ $a_3-a_2=11-7=4$ $a_4-a_3=14-11=3$ Thus we can see that the difference is not constant, thus it is not an arithmetic sequence.